Techniques to artificially generate aurora have been studied. Such studies are classified broadly into:
(i) academic studies exploring the mechanism of aurora generation by modeling the relationship between the sun emitting charged particles and the magnetic earth (see Japanese Patent Laid-Open No. Hei9-44081: Patent Document 1, for example); and
(ii) studies of techniques to generate curtains of aurora for the purpose of exhibition, e.g. for staging a spectacular macrocosmic show.
The aurora generation techniques for the purpose of exhibition in the above item (ii) utilizes numerous light leaking optical fibers to form a curtain to be illuminated with artificially light (see Japanese Patent Laid-Open No. Hei5-274903: Patent Document 2) or to be illuminated with laser light beams (see Japanese Patent Laid-Open No. Hei6-203610: Patent Document 3).
However, such imitated exhibitions of aurora lacks reality and impact because the do not utilize electric discharge phenomenon. In order to present an exhibition of artificial aurora with reality and impact, it is effective to utilize electric discharge phenomenon. It is experimentally known that light emission in irregular forms is observed between two electrodes set up in a vacuumed chamber by causing electric discharge between the two electrodes. The problem in the artificial aurora generation device of the art is that how it can generate a light emission in a curtain-like shape by electric discharge.
Disclosed in Japanese Patent Laid-Open No. Hei10-63180 (Patent Document 4) is an aurora generation device in which light emission in a planar form is generated by electric discharge. This invention comprises, as the requisite elements, a shield plate regulating excessive light emission and a center glass introducing electric discharge. It is reported that this invention enables to generate aurora in a belt-like shape.
As an improved invention of the above invention, an aurora generation device further comprising an earth electrode formed to imitate a terrestrial object is disclosed (Japanese Patent Laid-Open No. 2001-175163: Patent Document 5).
[Patent Document 1] Japanese Patent Laid-Open No. Hei09-44081.
[Patent Document 2] Japanese Patent Laid-Open No. Hei05-274903.
[Patent Document 3] Japanese Patent Laid-Open No. Hei06-203610.
[Patent Document 4] Japanese Patent Laid-Open No. Hei10-63180.
[Patent Document 5] Japanese Patent Laid-Open No. 2001-175163.